All categories

3 years ago

What does -9.8 m/s mean? And what does it mean if something has a negative velocity?

1 answer:

4 0

I can't guess what -9.8 m/s means until you tell me where it came from,
or what 'm/s' means.

If perhaps it has something to do with the acceleration of gravity on Earth,
then the correct figure is ' -9.8 m/s² '. That means that any object that
has no other force acting on it except gravity has its speed changing by
9.8 meters per second every second. Since it's gravity doing the job,
then the object's speed is either increasing down, or decreasing up.

If an object has negative velocity, then it's moving in the direction opposite
to the direction that you decided to call positive when you started doing the
problem.

For example, if you decide that up is positive and down is negative, and
then somebody drops a stone from the top of a tall building, then the
gravitational force on the stone is negative (pointing down), its velocity
is negative (it's falling towards down), and its acceleration is negative (its
speed towards down is getting faster and faster). Everything is negative,
only because you decided that up is positive and down is negative. It's
nothing to be worried about.

You might be interested in

1. How is electric potential energy similar to gravitational potential energy? How is it different? Where will an electron bound

Korolek [52]

Both ve similar equations
both are energies of one object w.r.t another 
differences- electric pe is due to electrostatic force and gravitational pe is due to gravitational force 
electric pe is > than gravitational pe since electrostatic force> gravitational force 
electron bound in an atom ll ve largest potential enegy in its ground state. i think hope it helps

7 0

3 years ago

The springs of a 1500 kg car compress 5.00 mm when its 68 kg driver gets into the driver's seat. Part A If the car goes over a b

elena-s [515]

Answer:

the frequency of the oscillation is 1.5 Hz

Explanation:

Given;

mass of the spring, m = 1500 kg

extention of the spring, x = 5 mm = 5 x 10⁻³ m

mass of the driver = 68 kg

The weight of the driver is calculated as;

F = mg

F = 68 x 9.8 = 666.4 N

The spring constant, k, is calculated as;

k = F/m

k = (666.4 N) / (5 x 10⁻³ m)

k = 133,280 N/m

The angular speed of the spring is calculated;

$\omega = \sqrt{\frac{k}{m} } \\\\\omega = \sqrt{\frac{133280}{1500} } = 9.426 \ rad/s$

The frequency of the oscillation is calculated as;

ω = 2πf

f = ω / 2π

f = (9.426) / (2π)

f = 1.5 Hz

Therefore, the frequency of the oscillation is 1.5 Hz

6 0

2 years ago

Two ice skaters are initially at rest. They push off and move in opposite directions. Ice Skater 1 has a mass of 90 kg and a vel

makvit [3.9K]

Answer:

vB = 8.57[m/s]

Explanation:

Since there is no external force that generates momentum, the amount of momentum is conserved so you will have the following equation

$m_{A}*v_{A}=m_{B}*v_{B}\\Where:\\m_{A}= 90[kg]\\v_{A}=10[m/s]\\m_{B}=105[kg]\\\\Therefore:\\\\v_{B}=\frac{m_{A}*v_{A}}{m_{B}}\\ v_{B}=\frac{90*10}{105}\\v_{B}=8.57[m/s]$

4 0

3 years ago

A(n) 71.1 kg astronaut becomes separated from the shuttle, while on a space walk. She finds herself 70.2 m away from the shuttle

denpristay [2]

Answer:

10.347 minutes.

Explanation:

According to F = ma, she exerts force on camera of the magnitude

F = 0.67Kg*12m/ $s^{2}$ = 8.04N, assuming it took her one second to accelerate camera to 12m/s, then by newtons third law, which says every action has equal and opposite reaction , the camera exerts the same amount of force on the astronaut which gives her acceleration of a = $\frac{8.04N}{70.2Kg} = 0.1130801680m/s^2$ .

and velocity of V = 0.1130801680m/s.

at this velocity , the astronaut has to cover the distance of 70.2 meters, it will take her 620.7985075s = 10.347 min to get to the shuttle (using S = vt).

4 0

3 years ago

1. Una bola de 0.510 kg de masa se mueve al este (dirección +x) con una rapidez de 4.80 m/s y choca frontalmente con una bola de

Grace [21]

Responder:

3,37 m / s, + ve x - dirección

Explicación:

Utilizando la ley de conservación de la cantidad de movimiento expresada por la fórmula;

m1u1 + m2u2 = (m1 + m2) v

m1 y m2 son las masas de los objetos

u1 y u2 son sus velocidades iniciales

v es su velocidad común

Dado

m1 = 0,519 kg

u1 = 4,80 m / s

m2 = 0,220 kg

u2 = 0 m / s (cuerpo en reposo)

Necesario

Velocidad común v

Sustituir en la fórmula los valores dados;

0,519 (4,8) + 0,22 (0) = (0,519 + 0,220) v

2,4912 + 0 = 0,739 v

2,4912 = 0,739v

Dividir ambos lados por 0,739

2,4912 / 0,739 = 0,739 / 0,739

v = 3,37 m / s

Por lo tanto, la rapidez de ambas bolas después de la colisión es de 3.37 m.s hacia la dirección x positiva, ya que m1> m2 y la velocidad común es positiva.

6 0

3 years ago